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We investigate what henselian valuations on ordered fields are definable in the language of ordered rings. This leads towards a systematic study of the class of ordered fields which are dense in their real closure. Some results have…

Logic · Mathematics 2019-02-06 Lothar Sebastian Krapp , Salma Kuhlmann , Gabriel Lehéricy

We study the definability of convex valuations on ordered fields, with a particular focus on the distinguished subclass of henselian valuations. In the setting of ordered fields, one can consider definability both in the language of rings…

The following conjecture is due to Shelah-Hasson: Any infinite strongly NIP field is either real closed, algebraically closed, or admits a non-trivial definable henselian valuation, in the language of rings. We specialise this conjecture to…

Logic · Mathematics 2022-07-04 Lothar Sebastian Krapp , Salma Kuhlmann , Gabriel Lehéricy

We introduce the notion of the definable rank of an ordered field, ordered abelian group and ordered set, respectively. We study the relation between the definable rank of an ordered field and the definable rank of the value group of its…

Logic · Mathematics 2026-01-13 Lothar Sebastian Krapp , Salma Kuhlmann , Lasse Vogel

We firstly show that due to their resplendency ordered henselian valued fields admit relative field quantifier elimination in the Denef--Pas language expanded by linear orders in the field and residue field sort. Secondly, we deduce from a…

Logic · Mathematics 2026-04-13 Lothar Sebastian Krapp , Floris Vermeulen

We give an explicit algebraic characterisation of all definable henselian valuations on a dp-minimal real field. Additionally we characterise all dp-minimal real fields that admit a definable henselian valuation with real closed residue…

Logic · Mathematics 2024-10-15 Lothar Sebastian Krapp , Salma Kuhlmann , Lasse Vogel

We prove the dp-finite case of the Shelah conjecture on NIP fields. If K is a dp-finite field, then K admits a non-trivial definable henselian valuation ring, unless K is finite, real closed, or algebraically closed. As a consequence, the…

Logic · Mathematics 2020-05-29 Will Johnson

We give a valuation theoretic characterization for a real closed field to be recursively saturated. Our result extends the characterization of Harnik and Ressayre \cite{hr} for a divisible ordered abelian group to be recursively saturated.

Logic · Mathematics 2015-10-27 Paola D'Aquino , Salma Kuhlmann , Karen Lange

Given a henselian valuation, we study its definability (with and without parameters) by examining conditions on the value group. We show that any henselian valuation whose value group is not closed in its divisible hull is definable in the…

Logic · Mathematics 2022-06-16 Lothar Sebastian Krapp , Salma Kuhlmann , Moritz Link

We show that every henselian valued field $L$ of residue characteristic 0 admits a proper subfield $K$ which is dense in $L$. We present conditions under which this can be taken such that $L|K$ is transcendental and $K$ is henselian. These…

Commutative Algebra · Mathematics 2010-03-31 Franz-Viktor Kuhlmann

We show that dp-minimal valued fields are henselian and that a dp-minimal field admitting a definable type V topology is either real closed, algebraically closed or admits a non-trivial definable henselian valuation. We give classifications…

Logic · Mathematics 2015-07-15 Franziska Jahnke , Pierre Simon , Erik Walsberg

We study the question of $\mathcal{L}_{\mathrm{ring}}$-definability of non-trivial henselian valuation rings. Building on previous work of Jahnke and Koenigsmann, we provide a characterization of henselian fields that admit a non-trivial…

Logic · Mathematics 2025-11-12 Margarete Ketelsen , Simone Ramello , Piotr Szewczyk

In his unpublished preprint "Definable Valuations" Koenigsmann shows that every field that admits a t-henselian topology is either real closed or separably closed or admits a definable valuation inducing the t-henselian topology. To show…

Logic · Mathematics 2016-03-31 Katharina Dupont

We present a unifying theory of fields with certain classes of analytic functions, called fields with analytic structure. Both real closed fields and Henselian valued fields are considered. For real closed fields with analytic structure,…

Logic · Mathematics 2009-08-18 Raf Cluckers , Leonard Lipshitz

Although the study of the definability of henselian valuations has a long history starting with J. Robinson, most of the results in this area were proven during the last few years. We survey these results which address the definability of…

Logic · Mathematics 2016-08-09 Arno Fehm , Franziska Jahnke

The paper establishes a relationship between finite separable extensions and norm groups of strictly quasilocal fields with Henselian discrete valuations, which yields a generally nonabelian one-dimensional local class field theory.

Rings and Algebras · Mathematics 2007-05-23 I. D. Chipchakov

We study the class of differentially henselian fields, which are henselian valued fields equipped with generic derivations in the sense of Cubides Kovacics and Point, and are special cases of differentially large fields in the sense of…

Logic · Mathematics 2025-02-11 Gabriel Ng

In this note we investigate the question whether a henselian valued field carries a non-trivial 0-definable henselian valuation (in the language of rings). It follows from the work of Prestel and Ziegler that there are henselian valued…

Logic · Mathematics 2014-08-01 Franziska Jahnke , Jochen Koenigsmann

Cluckers and Lipshitz have shown that real closed fields equipped with real analytic structure are o-minimal. This generalizes the well-known subanalytic structure $\mathbb{R}_{\mathrm{an}}$ on the real numbers. We extend this line of…

Logic · Mathematics 2024-04-17 Kien Huu Nguyen , Mathias Stout , Floris Vermeulen

We initiate the study of definable V-topolgies and show that there is at most one such V-topology on a t-henselian NIP field. Equivalently, we show that if $(K,v_1,v_2)$ is a bi-valued NIP field with $v_1$ henselian (resp. t-henselian) then…

Logic · Mathematics 2019-02-15 Yatir Halevi , Assaf Hasson , Franziska Jahnke
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